.NET programming tips and solution

The following c# function is used to validate the Mobile Number of US.It must be atleast 10 characters but not greater than 12 charactersIt may contain characters ( and -.It can contain Space.It must not containt alphabets or other charactersThe opening ( must be having Closing ).will return true if the mobile number is valid otherwise return false.private bool ValidateMobileNumber(String MobileNum){bool RtnVal = true;